UFH Manifold Not Receiving Hot Water

[Romanation]

Hi all,

 

Our current set-up is:

 

• Underfloor heating downstairs - 6 loops
• Radiators in the bedrooms upstairs
• Panasonic ASHP outside.

 

Everything has been working lovely for the past 7 years however...due to a new arrival and the need for more bedrooms...we had an extension built on the side of the house and the ASHP moved roughly 3m over. The problem I'm having is that whilst we can quite happily get hot water, the heating side of things is playing up. The radiators upstairs work fine - we have a wireless thermostat upstairs which when set to call for heat will do until the TRV's are satisfied. The underfloor heating however does not get warm unless the upstairs is calling for heat and even then it's lukewarm at best. This previously wasn't the case and we could have the underfloor on downstairs with the upstairs off. The pipes leading to the mixer valve >> pump >> manifold are currently stone cold despite the room thermostat being set to 27c for the last few hours. Pipework under the stairs where the tank sits are hot to the touch.

 

Plumber insists all he has done is add a new radiator to the upstairs bedroom, connecting into the existing pipework as well as add 2 new loops to the manifold downstairs for the additional rooms. We have had one of the guys out who worked for the original company that installed the system back in 2015. He's said that there is air in the loops and it has blown the pump. He appears to have changed the pump and (apparently) cleared the air out from the loops. Problem is when I came home (wife was in the house when he was working during the morning). the issue is still there. 

 

For additional context the Panasonic control console is throwing up an error - H62 - which is to do with flowrate. 

 

I'm now at a bit of a loss as to what is causing the issue. Possible thoughts (but keep in mind I know next to nothing about plumbing) are that a valve somewhere isn't working as it should to pass hot water to the underfloor system?

 

Any thoughts/advice greatly appreciated,

[JohnMo]

I wound start by

 

Turning off the new UFH loops and new radiators, so you start from there you were prior to the modification.

 

Do things methodically.

1. Switch off the upstairs radiators via thermostat and same for UFH.

2. Switch one system on via thermostat, does the ASHP startup?

3. Are you getting the correct temps yes or no.

4. Switch off everything again

5. Repeat same for other system

6. Try both systems what happens.

7. Bring on the new parts of the system one at a time, what happens?

 

Post reply with system photos 

[ProDave]

Clearly the alterations have messed things up.

 

Get both the electrician and the plumber to sort it.  They broke it, they fix it.

[Conor]

Three possible problems. Could be one, some or all.

 

1. Configuration. Something not right with a pump/valve/controller. Impossible to say from here 

2. Airlock / blockage in a pipe somewhere.

3. HP is incapable of delivering the additional heat load. 

 

And another, almost certain, 

Your plumber could be out of thier depth.

[Romanation]

So having spent the last 10 days playing around with various combinations I can confidently answer these questions:

 

1. Switch off the upstairs radiators via thermostat and same for UFH.

2. Switch one system on via thermostat, does the ASHP start-up? - Thermostat for upstairs -  yes. ASHP fires up.

3. Are you getting the correct temps yes or no. - Yes,  hot water flows to towel rail and radiators, then switches off once TRV's are happy with room temp (I have now learnt what the numbers on those things correlate to 😃).

4. Switch off everything again

5. Repeat same for other system. - Thermostats for each zone downstairs - yes, ASHP fires up. Continues to for about 10mins when it winds down and the console throws up an H62 error message. Pipework to manifold never gets warm let alone hot.

6. Try both systems what happens. - Thermostats for upstairs and zones downstairs. ASHP fires up. Rads and towel rail get warm. Manifold gets warm water however after a while the H62 error message appears. 

7. Bring on the new parts of the system one at a time, what happens? Same as the old/original zones coming on. Flow error and not heating to the manifold.

 

Pic below is the manifold under the kitchen counter. The actuator was previously on but has been left off today. Doesn;t seem to have made a difference to the issue.

 

 

Below the stairs. Apologies for the mess of network cables and disused satellite cables. Could the Honeywell valve in the middle was be cause of the issue?

 

Edited December 11, 2023 by Romanation

[Romanation]

Took the cover off the ASHP at the week end. Sister in-law next door has the same setup (joint build at the time) so I took pictures of both heat pumps to compare. Focused on the efficiency pump however I did photograph all of mine and I notice the 3 port valve only has 2 connections on the right hand side going to it. I'm going to take the cover off SIL's to compare (sadly didn't take a photo of her ASHP wiring) to see if I can spot a wiring issue. Electrician originally missed the tank sensor so it's a possibility that they're fluffed up something here.

 

Edited December 11, 2023 by Romanation

[Nickfromwales]

The 3 port valve is a diverter and not a mid-position, so will only have the 3 wires (brown, blue, green/yellow) so looks correct at a glance. It simply gets energised to change state (central heating or hot water) so defo isn't a 4 or 5 wire valve .

 

29 minutes ago, ProDave said:

Clearly the alterations have messed things up.

 

Get both the electrician and the plumber to sort it.  They broke it, they fix it.

+1, get on the phone and get them both back immediately and tell then if can't make it work you want a refund so you can pay someone who can. Sounds like a wiring / configuration issue to me, but really hard to say from afar.

[Romanation]

Aware of the amount of posts I see where someone figures out what was wrong but doesn't report back so here I am...

 

So it turns out the plumbers cocked up and put the flow/return pipes in the wrong way round to the ASHP. Corrected today and all working again.

Edited December 13, 2023 by Romanation